Conventional menu navigation devices and interface devices (e.g. a touch pad) use sensors which are placed above switches or buttons to determine centroids and allow a user to indicate position or invoke functions associated with the switches. Capacitive sensors may be used to determine a position of an object, such as a finger. For example, a touch pad may use capacitive sensors to allow a user to move a cursor around and use switches to invoke right and left click functions.
FIGS. 1A-1C show a conventional design for a capacitive sensor and switch based device. Specifically, FIG. 1A shows a conventional arrangement of capacitive sensors 102-116, FIG. 1B shows a conventional arrangement of switches 120-126, and FIG. 1C shows a conventional interface device which has capacitive sensors 102-116 above switches 120-126.
If the user intends to press the switch 120, by the time switch 120 is pressed, debounced, and reported, the adjacent capacitive sensors 102 and 116 will already have measured a change in capacitance and reported the activity. This premature reporting of activity often leads to jittery and unintentional performance of functions associated with the sensors (e.g., position) and thus is undesirable. For example, if switch 120 corresponded to a play button and the capacitive sensors corresponded to volume control, a user trying to push play may unintentionally change the volume.
Conventional designs have attempted to solve this problem by delaying the responsiveness of the sensing until it has been fully determined that a switch has been pressed. For example, a system may wait for a sufficient amount of time for a switch press to be completed before responding to any user input from the capacitive sensors. This non-response period means that a user may be trying enter commands but the system will not register them and thus the user interface will not be smooth and responsive leading to an undesired experience.